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Environmental Issues

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Published in: Botany
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NCERT BASED NOTES USEFUL TO ACADEMIC AND NEET EXAM

Dhanalakshmi L / Madurai

12 years of teaching experience

Qualification: M.Sc (University Of Madras , Chennai - 2006)

Teaches: Bio Technology, Biology, Botany, Home Science, Zoology, Bio Chemistry, Food Inspector Exam, Forest Department Exam

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  1. ENVIRONMENTAL ISSUES 16 June 2022 17:32 Human population is increasing tremendously; therefore there is a lot of demand for food, electricity, clothing, roads, housing, vehicles etc. These are exerting a lot of pressure on land, water, air and other resources. This leads to pollution and degradation of the environment and biodiversity that is a part of it. ollution is any undesirable change in the physical, chemical or biological haracteristics of air, water or land which has the potential to adversely affect uman life, life of desirable species, naturalresources, industrial processes and ultural assets Pollutants: Agents which cause pollution. 11 CPCB: Central Pollution Control Board Il FOAM: Friends of Arcata Marsh Il JFM (Joint Forest Management): Introduced by the Government of India in 1980s to work closely with local communities for protecting and managing forests. HARMFUL EFFECTS HARMFUL EFFECTS NOISE POLLUTION E-WASTES AGRO CHEMICAL WASTES CONTROL OF AIR POLLUTION USE OF CNG ELECTROSTATIC PRECIPITATOR SCRUBBER CATALYTIC CONVERTER USE OF LEAD FREE FUEL AIR POLLUTION POLLUTION SOIL POLLUTION SOLID WASTES WATER POLLUTION BIOCHEMICAL OXYGEN DEMAND (BOD) ALGAL BLOOM BIOMAGNIFICATION BIODEGRADABLE New Section I Page I
  2. AGRO CHEMICAL WASTES RADIO ACTIVE WASTES HOSPITAL WASTES BIODEGRADABLE BIOMAGNIFICATION RECYCLABLE EUTROFICATION NON BIODEGRADABLE The Government of India has passed the Environment (Protection Act, 1986 which ims to protect and improve the quality of air, water and soil. Air Pollution: In our atmospheric air, we have fixed amounts of various components like oxygen, nitrogen, carbon di oxide and all such gases. But due to Excessive use of combustion fuels and many other factors, this fixed amount is moving towards an imbalance. Moreover, some harmful substances like mercury and lead particulates are also present in the air. This phenomenon is termed as Air Pollution. Componet Symbol Voltme Nitrogen 780/ Oxygen 21% Carbon dioxide and other gases. 03% Inert gases (mainly argon). "iter Jipor 1% CONTROL OF AIR POLLUTION : Nitroten Oxygen Argon Carbon Dioxide 02 C02 78.084% 20947% 0.934% 0.033% 0-2% Water Vapor 1120 Argon Other Traces Air pollution can be controlled by following methods: 1. Electrostatic precipitator: This device is very efficient, used to remove particulate matter from air. This device can remove 99% particulates which are present industrial or thermal power plant's exhausts. In this device electrode wire at thousand volts are used and dust particles passed out through this device. New Section I Page 2
  3. Electrons released get attached to dust particles giving them negative charge. The collecting plates which are grounded attract these charged particles. 2. Scrubber: This device is used to remove,gaseous ollutant like sul hur dioxide. The exhaust is passed through a spray of water and lime, which on reacting with sulphur dioxide form precipitate. 3. Catalytic converter: This is a device fitted in automobiles for emmission of gases. In catalytic converter metals like rhodium and platinum palladium act as catalyst. Only unleaded petrol can be used in vehicle in which catalytic converter is fitted. Clean sepia y Civschatge Negative*y chergae wire Cåean acr Dirty . Dust particies plate Electroslarse vyecipi!alor Scrubber New Section I Page 3
  4. 2 smoke particles are attracted to the collecting plates 1 smoke particles pick up a negative charge waste gases without smoke particles waste gases containing smoke particles positively charged collecting plate collecting plates are knocked to remove the smoke particles negatively charged grid 3 Proper maintenance of automobiles along with use of lead-free petrol or diesel can reduce the pollutants they emit. atalytic converters, having expensive metals namely platinum-palladium and hodium as the catalysts, are fitted into automobiles for reducing emission of oisonous gases. New Section I Page 4
  5. Catalytic Converter CO - Carbon Monoxide HC - Hydrocarbons - Nitrogen Oxides C02 - Carbon Dioxide H20 - Water N2 - Nitrogen 9- Catalyst Substrate (Catalytic Active Material) Major reaction co + H4C2 + + 2H20 CO + NOx—+C02 + N2 @ Science Media Group Motor vehicles equipped with catalytic converter should use unleaded petrol because lead in the petrol inactivates the catalyst. In India, the Air (Prevention and Control of Pollution) Act came into force in 1981, $ut was amended in 1987 to include noise as an air pollutant. extremely high sound level, 150 dB or more generated by take off of a jet plane or rocket, may damage ear drums thus permanently impairing hearing ability _Even chronic exposure to a relatively lower noise level of cities may permanently damage hearing abilities of humans. Noise also causes sleeplessness, increase heart beat, alteredbreathing pattern, thus considerably stressing humans; In the 1990s, Delhi ranked fourth among the 41 most polluted cities of the world. Public interest litigation (PIL) was filled in the Supreme Court of India. The government was asked to take, within a specified time period, appropriate measures, including switching over the entire fleet of public transport, i.e., buses, from diesel to compressed natural gas (CNG). CNG burns most efficiently, unlike petrol or diesel, in the automobiles and very little of it is left unburnt. New Section I Page 5
  6. SCHEMATIC PIAGRAM BIOGAS TO RSION Moreover, CNG is cheaper than petrol or diesel, cannot be siphoned off by thieves and adulterated like petrol or diesel. The main problem with switching over to CNG is the difficulty of laying down pipelines to deliver CNG through distribution points/ pumps and ensuring uninterrupted supply imultaneously parallel steps taken in Delhi for reducing vehicular pollution include hasing out of old vehicles, use of unleaded petrol, use of low-sulphur etrol and iesel, use of catalytic converters in vehicles, application of stringen Auto Fuel Policy: The Government of India has laid out a road map to cut down the vehicular air pollution in many cities of India. The goal is to reduce sulphur down to 35% of the fuel. The Bharat Stage Il was applied to all automobiles in all cities from April, 1,2005. The cities like Delhi, Mumbai, Chennai, Kolkata have to meet Euro emission norms from April 1, 2005 and Euro IV Emission norms from April, 1, 2010. Water pollution: It's the pollution of water bodies with substances like domestic wastes, industrial, hermal, mineral, toxic, nitrogen & phosphorous rich wastes. The nutrient rich astes multiply the algae concentration in the water bodies & this leads of depletion New Section I Page 6
  7. f oxygen in these bodies & hence leads to the death of fish and other biodiversity in he area Water (Prevention and Control of Pollution) Act, 1974 to safeguard our water Proteins 99.9% Water 70 Organic Fats Solids Inorganic Sediment Salts Metals Carbohydrates It's harmful effects include: BIOCHEMICAL OXYGEN DEMAND (BOD) BOD refers to the amount of oxygen that would be consumed if all the organic matter in one litre of water were oxidized by bacteria. The BOD test measures the rate of uptake of oxygen by micro-organisms in a sample of water. Indirectly, BOD is a measure of the organic matter present in the water. The greater the BOD of waste water, more is its polluting potential. Fish killed and Disappearance ofclean water Reappreance ofclean water organisms BOD (high) Dissolved 02 (low) Sewage discharge Dissolved 02 (high) BOD (low) Direction of Flow Concentration Algal Bloom: Presence of large amounts of nutrients in water causes excessive growth of algae, called an algal bloom. New Section I Page 7
  8. Harmful effects of algal bloom are: 1. Fish mortality. 2. Deterioration of water quality. 3. Toxic to animals and human beings. It is necessary to control water pollution as it leads to diseases like jaundice, cholera, typhoid, dysentery, dengue, malaria etc many of which are very hard to cure. Biomagnification: It is increase in the toxicity among the food chain at successive trophic levels. This phenomenon is well known with mercury and DDT. Water (0.003 ppb) (0.0025 ppm) Fish eating birds (5 ppm) Zooplankton (0.04 ppm) Large fish (2 ppm) Small Fish (0.5 ppm) This happens because a toxic substance accumulated by an organism cannot be metabolised or excreted, and is thus passed on to the next higher trophic level. High concentrations of DDT disturb calcium metabolism in birds, which causes thinning of eggshell and their premature breaking, eventually causing decline in bird populations. Eutrophication is the natural aging of a lake by nutrient enrichment of its water. Accelerated Eutrophication: Eutrophication is the aging of a lake to convert into land, which generally takes 1000s of years or more. But human activities have accelerated this natural process & as a result many lakes are already extinct. It is caused due to dumping of nutrient rich and thermal waste into lakes. New Section I Page 8
  9. 12B16.2.4 — Case Study of Integrated Wastewater Treatment An initiative in town of Arcata, situated along the northern coast of California. Integrated treatment of wastewater including sewage Artificial Process Natural Process Town's people collaborated with biologists from Humboldt State University. Avanti Dry composting toilets called Ecosan toilets can be used for the disposal of human excreta in an ecological way. No water is required in this toilet. Human excreta is converted into a resource as it forms a natural fertiliser. Ecosan toilets are functional in many parts of Kerala and Sri Lanka. Solid wastes It refers to everything that goes out in trash. Municipal solid wastes are wastes from omes, offices, stores, schools hospitals, etc. that are collected and disposed by the unicipality. The municipal solid wastes generally comprise paper, food wastes, plastics, glass, metals, rubber, leather, textile, etc. Burning reduces the volume of the wastes, although it is generally not burnt to completion and open dumps often serve as the breeding ground for rats and flies. Sanitary landfills were adopted as the substitute for open-burning dumps. In a sanitary landfill, wastes are dumped in a depression or trench after compaction, and covered with dirt everyday. Everyday humans produce millions of tonnes of waste all over the world. But what happens to this waste produced? In many countries the waste produced is burnt to reduce it's volume, but burning is not an effective way to reduce waste as it causes pollution & release of toxic wastes. New Section I Page 9
  10. n countries like Germany, the methane produced from the wastes is collected & used s fuel, & the decomposed waste is used as fertilizer as it is highly rich in nutrients It is classified into three main types: • Bio Degradable waste. • Non-Bio Degradable waste. • Recyclable waste. Radioactive wastes he waste produced from the nuclear fission of heav atoms such as uranium thorium tc for the production of power is radioactive waste his waste is highl toxic and causes mutations and cancer. It has to be dealt with tmost caution The nuclear waste should be stored after heavy treatment and packed in special containers. It should be buried deep under the ground for minimum of 60 — 80 years for the waste to stabilize. Greenhouse effect and global warming Global warming refers to the heating up of the Earth due to greenhouse effect. Greenhouse effect is caused when gases such as C02, CH4 etc increase in the atmosphere & this leads to the heating up of the earth as these are good absorbers of heat. These gases prevent the excess heat from leaving the Earth's atmosphere thus resulting in greenhouse effect. New Section I Page 10
  11. Natural Greenhouse Effect sun Human Enhanced Greenhouse Effect SUN Greenhouse effect Depletion of ozone layer The depletion of ozone layer is one of the major cause for cancer. Ozone is formed in the stratosphere by the effect of UV rays on 02. The thickness of ozone is measured in Dobson units. to SO km O to 10 km STRATOSPHERE OZONE LAYER TROPOSPHERE EARTH The UV rays act on the CFCs to release freons that react with ozone to release pure oxygen. The freons merely act as catalysts & are not used up in the reaction. Hence the released freons have a continuous harmful effect on the ozone layer. he CFCs released in the lower part of the atmosphere move upwards towards the New Section I Page I I
  12. outh pole, hence depleting the ozone la er over Antarctica Ozone L e.•yer pos p he Ha C..j••.•• rays CFC's etc STEPS LEADING TO OZONE DEPLETION UV-rays split CFCs and release atomic chlorine (C') UV-rays also split ozone into oxygen. (03 -+(UV Chlorine atoms trap oxygen atoms and ozone is not formed again from oxygen. This leads to depletion of ozone in the stratosphere. Chloroflurocarbons : Chloroflurocarbons CFC3 are major cause of depletion of ozone layer. These compounds leaks in one way or other, escape and diffuse to stratosphere. These ultraviolet radiations break the C-CI bond in CFC13 and generate chlorine free radicals as Equation : CFC13 (W) > CFC12 + These free radicals are very reactive. They react with ozone to form oxygen as Equation : 03 + a > 03 + OCI* > 02 New Section I Page 12
  13. Ozone Destruction Cycle 1 Oxygen molecule (02) 00 CIO +0 Oxygen atom (O) Chlorine atom (Cl) Chlorine catalytic Chlorine monoxide (CIO) 0+02 -9 00+02 00+0 *Cl+02 Ozone (02) Ozone destruction Oxygen molecule (02) Net: 0+03 -+ 202 Sign of ozone depletion were first noticed over Antarctica in 1980s. Since 1990s depletion have also been recorded over the Arctic. Ozone Hole : Large area of thinned ozone layer over Antartica. Deforestation eforestation is the conversion of forested areas to non-forested ones. According to an estimate, almost 40 per cent forests have been lost in the tropics, compared to only 1 per cent in the temperate region. The cutting down of trees for wood for furniture, fire wood, paper, to make New Section I Page 13
  14. cigarettes, to clear land for cultivation, due to the expansion of cities etc. Slash and burn agriculture, commonly called as Jhum cultivation in the north-eastern states of India, has also contributed to deforestation. Deforestation has a very harmful effect on the environment. It leads to desertification, global warming, acid rain, depletion & pollution of ground water levels, loss of biodiversity in the affected areas etc. There are various efforts to conserve the forests. Chipko Movement of Garhwal Himalayas in 1974 In India Amrita Devi Bishnoi Wildlife Protection Award is given to individuals or organizations that show courage & dedication towards biodiversity. The Government of India in 1980s has introduced the concept of Joint Forest Management (JFM) so as to work closely with the local communities for protecting and managing forests. There are various ways in which we can help to conserve trees: Avoiding the use paper to read books & news. Reforestation Controlling growth of Human population & the expansion of cities. Forming groups and communities to fight against deforestation. Seeking help from governmental and non — governmental organizations for the conservation forest. New Section I Page 14
  15. New Section I Page 15

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